HANOI -- Vietnamese President Tran Dai Quang has not been seen in public for nearly a month with no explanation from the government, fueling speculation about a power struggle and talk that the nation's top leader -- the head of the Communist Party -- could step down next year.

Breach of protocol

The itinerary of Turkish Prime Minister Binali Yildirim's visit to Vietnam was abruptly revised Tuesday night. The amended version sent out to the media left out a meeting with Quang originally scheduled for the next day. The Ministry of Foreign Affairs gave no reason for the change.

State guests typically meet with the general secretary of the Communist Party, the president, the prime minister and the speaker of parliament. The president plays a particularly important role, handling such events as arrival ceremonies and parties. The lack of any indication that Quang is outside Vietnam means he probably is still in the country, making his absence all the more extraordinary in a communist nation that places great weight on the political pecking order.

Quang's last public appearance was July 25, when he met with Nikolai Patrushev, secretary of Russia's security council. The president has since missed such important events as last Friday's anniversary of the establishment of the People's Public Security Force, the core of Vietnam's police.

This occasion is of particular significance to Quang. The force is under the purview of the president and Quang was previously public security minister after spending decades in that field. His presence at the event was also vital from a political standpoint, to solidify his influence. Yet he failed to show up, simply sending a congratulatory message with words of encouragement.

Communist Party General Secretary Nguyen Phu Trong has stepped up diplomatic activities as if to cover for the apparent absence of the president, who typically takes on such duties. Trong visited Indonesia from Tuesday through Thursday, meeting with President Joko Widodo. Next up is a three-day trip to Myanmar, where Trong will speak with President Htin Kyaw. This marks the first visit to Myanmar by a sitting general secretary in 20 years, since Do Muoi went there in 1997.

Coincidence?

Quang's disappearance from the public eye is not the only odd development in Vietnamese politics over the last few months. It was announced July 30 that Dinh The Huynh, a standing member of the secretariat of the party's Central Committee who was tipped as a candidate to succeed Trong, would be replaced by Politburo member Tran Quoc Vuong due to illness. The odds of Huynh returning to his position are dim, an expert on Vietnamese politics said, citing rumors that he is seeking cancer treatment.

The following day, authorities detained Trinh Xuan Thanh, a former chairman of state-run PetroVietnam Construction, for allegedly causing $150 million in losses at the company. The German government accused Vietnam a few days later of abducting Thanh from Berlin. Hanoi called the statement regrettable without addressing the claim's veracity.

Thanh is said to have ties to former Prime Minister Nguyen Tan Dung, who was forced out last year, and to Dinh La Thang, who was ousted as party secretary of Ho Chi Minh City in May.

Vietnam's leaders are chosen at twice-a-decade party congresses, with the next one scheduled for 2021. But the 73-year-old Trong's advanced age and the fact that he took the helm back in 2011 have fueled speculation that he could hand over power to a successor next year.

The most likely option is Quang, now seemingly absent. Huynh's illness has effectively taken him off the list. Thanh's apparent kidnapping ties into this as well, given his connection to Dung, a former political rival of Trong's. Whether all these developments can be chalked up to coincidence remains unclear.

The next big occasion is National Day, which celebrates Vietnam's declaration of independence. Hanoi watchers will be looking to see whether Quang puts in an appearance Sept. 2.